1. Field of the Invention
The present invention relates to a wound dressing, and more particularly to a wound dressing which is suited for treatment of wounds, for example burns or trauma.
2. Description of the Prior Art
To date, various dressings have been developed to treat a broad range of skin defects due to burns, trauma or wounds.
While a variety of structural contrivances have been made for such wound dressings, those being often used at present are in the form that a silicone film is adhered to one side of a fabric or sponge structure to inhibit the invasion of bacteria This structure creates a primary vital adhesion by absorbing the exudate from the affected site to form fibrin, and in turn enables secondary vital adhesion by ensuring the subsequent penetration of fibroblasts and capillaries, thus resulting in the strong adhesion of the dressing to the wound surface. However, since the silicone film allows body fluid proteins to accumulate under the film, it has a great danger of becoming a source of nourishment for bacterial growth present on the wound surface, so that it has the shortcoming that the healing of wound is disturbed.
In the sponge structure as described above, moreover, its required performances such as good contacting ability with the above-mentioned exudate and blood, the efficiency of drug release, the good dressing ability of affected sites, etc. have been examined less sufficiently to date. For example, the structure disclosed in the U.S. Pat. No. 3,113,568 includes a barrier 20 which is made of foam having a network structure provided under a pad 11, as illustrated in FIGS. 12 and 13. Unit cells 21, which constitute this barrier 20, present a polyhedral structure having each face 22 (which is three-dimensionally linked by leg-like links 23 to become pores) formed. Therefore, this structure is simply network-like, not structurally satisfying each of the above-mentioned required performances to a sufficient extent. In other words, since the network-like structure is only linked by the leg-like links 23, it involves the following problems: the contact area having contact with exudate and blood is not sufficient; the mechanical strength of the network object is low; the drug dispersed from the network-like structure (which is contained in the structure beforehand) is released less efficiently; and the barrier effect on bacteria still remains to be improved. These problems are found generally in other known sponge structures.